Tooth restoration.



FREDERICK S TANWOOD WELDEN, OF NEW YORK, N". Y ASSIGNOB TO MAUDE FRANCES WELDEN, OF NEW YORK,

TOOTH RESTORATION.

No Drawing.

Specification of Letters Patent.

Patented Nov.26,1l9ll2.

following specification contains a full, clear,

and exact description.

My invention comprises a process for restoring a broken, decayed or malformed tooth, in substantially exact'simulation of a natural or properly formed tooth, both in color, shape and texture.

My improved composition used in carrying out my process consists of mlneral base of the silicate group, such as feldspar and silica suitably combined with an appropriate fiux, such as borax, so that'upon the application of heat the compound may be reduced to a fluid condition which will enable it to be run into molds of the proper form for the production of the restoration. With the basic ingredients above named, I also combine other materials, such as bone ash, oxid of tin or infusorial earth, to impart opacity and the requisite texture to the compound. In order to secure the proper color or shade of color, I also. add thereto oxids of the various metals, or other substances, such for instance as oxid of titanium or oxid of iron, for creams or yellows, and oxid of iridium or platinum sponge for grays. The temperature required to reduce this compound to a fluid condition will vary with the proportions of the materials and their refractoriness, but I find that the following proportions will enable me to reduce the composition to fluid conditionat about 1800 degrees Fahrenheit:

Feldspar 27 parts Silica 10 Calcined borax 28 Bone ash 2O Ammonium carb 3 Magnesium sulfite 6 Coloring matter as required. This is a relatively low fusing point,

which is a great advantage in the practical ing the composition, allow it to harden in cakes or small slabs.

An eflicient way of forming the casting is to prepare a wax pattern of the portion to be restored by the usual method. A sprue Wire of proper size is heated and inserted in the pattern after which the pattern is carefully cleaned. The sprue and pattern are then mounted on a conical' crucible former. The investment compound as used by dentists is mixed and a small portion is painted over the wax pattern with a soft brush to avoid air bubbles. The former and pattern are then placed in the crucible ring and'the latter filled with investment compound. After the investment has set the sprue is removed from the pattern and crucible. The crucible is next carefully dried by heating it gradually until the wax pattern is burned out leaving a mold of the restoration in the investment compound with the gate leading thereto. The crucible is then pre-heated to approximately the fusing point of the silicate material and placed on a vacuum or pressure casting machine of type commonly used by dentists. I

filling of the mold. To obtain a stronger and tougher casting the crucible and contents are slowly heated and cooled several times to anneal the silicate material. The casting is then removed from the mold and cleaned and polished after which it is cemented in position on the tooth.

It is obvious that fillings, inlays, caps, whole teeth and even bridges may be cast by my process.

I claim- 1. The process of forming artificial dentures which consists in making a mold of the desired size and shape, pre-heating the mold, reducing a silicate compound to a fluid condition with a nonoxidizing flame, running the fused silicate into the mold under pressure and maintaining the heat and pressureuntil the mold is completely filled.

2. The process of forming artificial dentures which corisists in makixig a mold gof contents and re-heating the same to anneal the desired size and shape, reducing a silithe casting. I e

.cate compound to a fluld condition under FREDERICK A W WELDEN.

heat and runningthe same while fluid into 5 the mold, maintaining the heat on the mold Witnesses: and silicate until the former is completely EDWARD BULL,

filled with the latter, cooling the mold and ARTHUR H. BULL. 

